def add_local_mode()

in tools/upgrade/filesystem.py [0:0]

• 32 lines of code
• 13 McCabe index (conditional complexity)

def add_local_mode(filename: str, mode: LocalMode) -> None:
    LOG.info("Processing `%s`", filename)
    path = Path(filename)
    text = path.read_text()
    if "@" "generated" in text:
        LOG.warning("Attempting to edit generated file %s, skipping.", filename)
        return

    lines: "List[str]" = text.split("\n")

    # Check if a local mode is already set.
    for line in lines:
        for local_mode in LocalMode:
            if re.match(local_mode.get_regex(), line):
                return

    def is_header(line: str) -> bool:
        is_comment = line.lstrip().startswith("#")
        is_pyre_ignore = (
            re.match("^[ \t]*# *pyre-ignore *$", line)
            or re.match("^[ \t]*# *pyre-fixme *$", line)
            or re.match("^[ \t]*# *type: ignore *$", line)
        )
        return is_comment and not is_pyre_ignore

    # Add local mode.
    new_lines = []
    past_header = False
    for line in lines:
        if not past_header and not is_header(line):
            past_header = True
            if len(new_lines) != 0:
                new_lines.append("")
            new_lines.append(mode.get_comment())
        new_lines.append(line)
    new_text = "\n".join(new_lines)
    ast.check_stable(text, new_text)
    path.write_text(new_text)